Exploring hospital practice types and their impact on glomerular pathologic patterns: Insights from the largest kidney biopsy cohort in Thailand.

BACKGROUND: This study aims to investigate the influence of different kidney biopsy practices on the prevalence of glomerular pathologic patterns in the largest kidney biopsy registry in Thailand. METHODS: We conducted a retrospective review of kidney biopsy records from the period between 2000 and 2014. The records were obtained from 2 major institutions: King Chulalongkorn Memorial Hospital, a large university-based hospital, and the Kidney Center Bangkok Hospital, which provides pathology services to hospitals throughout Thailand. The study included native kidney biopsies from all provinces in Thailand, excluding paediatric patients, kidney transplant recipients, and cases of inadequate and repeated biopsies. Patient demographics, indications for biopsy, and final glomerular diagnoses were compared across different hospital practice settings: university (UVH), private (PVH) and public (PBH). RESULTS: A total of 5893 eligible native kidney biopsies were identified from a pool of 7005 biopsies conducted over a 15-year period in 25 provinces throughout Thailand. The 3 most common indications for biopsy were suspected kidney involvement in systemic lupus erythematosus (SLE) (29%), nephrotic syndrome (NS) (29%), and acute glomerulonephritis (AGN)/rapidly progressive glomerulonephritis (RPGN) (13%). The leading indication for biopsy differed across practice types, with suspected kidney involvement in SLE being the primary indication in UVH, while NS took precedence in both PBH and PVH practices. Notably, UVH performed fewer kidney biopsies for asymptomatic urinary abnormalities and diabetes-related indications compared with PVH and PBH. The leading glomerular diagnoses correlated with the biopsy indications, with lupus nephritis (LN) being the most common diagnosis in UVH and PBH practices, whiles immunoglobulin A nephropathy was the predominant diagnosis in PVH practice. CONCLUSION: Hospital practice types significantly impact the prevalence of glomerular pathologic diagnosis patterns in kidney biopsy data, highlighting the importance of considering this influence in epidemiological comparisons.

Clinicopathological Characteristics and Impacts on Clinical Outcomes of Thrombotic Microangiopathy Lesions in Patients with Immunoglobulin A Nephropathy in Thailand.

INTRODUCTION: More reports of thrombotic microangiopathy (TMA) in immunoglobulin A (IgA) nephropathy suggest its association with poor clinical outcomes. However, the prevalence and clinical significance of TMA in IgA nephropathy have not been widely studied in different populations. METHODS: Kidney biopsies of all patients with primary IgA nephropathy from 1995 to 2015 at the King Chulalongkorn Memorial Hospital, Thailand, were retrospectively reviewed and reclassified by two pathologists following the Oxford MEST-C classification. TMA lesions were detected based solely on light microscopic findings. Associations between the presence of TMA and clinical data, other pathologic findings, and clinical outcomes were studied. RESULTS: Among 267 patients with primary IgA nephropathy, 166 had adequate clinical data and kidney tissues for the analysis. TMA was observed in 21 patients (13%) and was associated with higher mean arterial pressure (MAP), history of malignant hypertension, higher proteinuria, and lower estimated glomerular filtration rate (eGFR) at diagnosis compared to those without TMA. According to the Oxford MEST-C classification, TMA showed a significant association with severe tubular atrophy/interstitial fibrosis (T2) but not with mesangial hypercellularity (M1), endocapillary hypercellularity (E1), segmental glomerulosclerosis (S1), or crescents (C1-2). After a median follow-up of 50 months, patients with TMA had a significantly higher risk of progression to end-stage kidney disease (ESKD) (hazard ratio [HR] 5.8, 95% confidence interval [CI]: 3.1-10.9) and all-cause mortality (HR 3.4, 95% CI: 1.3-8.8). After adjusting for baseline eGFR, MAP, proteinuria, and other pathological lesions, TMA remained an independent predictor of ESKD (adjusted HR 2.4, 95% CI: 1.1-5.4). CONCLUSIONS: Kidney TMA in IgA nephropathy is associated with advanced disease stages, carries a poor prognosis, and thus should be considered in the pathological classification of IgA nephropathy.

A Case of Extranodal NK/T-cell Lymphoma Infiltrating Kidneys, Presenting With Hematuria and Proteinuria With False-Positive Serum Anti-proteinase 3, and Mimicking Granulomatosis With Polyangiitis.

We report a case of misdiagnosed extranodal NK/T-cell lymphoma, nasal type, mimicking granulomatosis with polyangiitis (GPA). A 30-year-old male presented with chronic non-resolving right paranasal sinusitis for two years accompanied by multiple generalized cutaneous nodules, and subnephrotic-range proteinuria. Biopsies from skin lesions and paranasal sinuses demonstrated leukocytoclastic vasculitis and necrotizing granulomatous inflammation, respectively. Serum proteinase 3 (PR3)-antineutrophilic cytoplasmic antibody (ANCA) was positive, suggesting the diagnosis of GPA based on the 2022 American College of Rheumatology/European Alliance of Associations for Rheumatology Classification Criteria for GPA. A kidney biopsy was not pursued due to the cause of glomerulonephritis (GN) being clinically evident, per the KDIGO 2021 GN Clinical Practice Guidelines. Immunosuppression was administered, which led to a transient improvement in clinical symptoms. However, subsequent kidney biopsy and other organ biopsies with cytogenic and molecular tests eventually confirmed extranodal NK/T-cell lymphoma infiltrating kidneys, skin, and paranasal sinuses. Physicians should always consider the possibility of hematologic malignancy in young adults presenting with multiple-organ involvement with vasculitic lesions or pauci-immune crescentic GN, albeit positive ANCA serologies. Kidney biopsy with cytogenic support should be performed to exclude threatening diseases, especially in atypical cases such as in young patients despite a context of compatible manifestations with other syndromes.

An ex vivo culture model of kidney podocyte injury reveals mechanosensitive, synaptopodin-templating, sarcomere-like structures.

Chronic kidney diseases are widespread and incurable. The biophysical mechanisms underlying them are unclear, in part because material systems for reconstituting the microenvironment of relevant kidney cells are limited. A critical question is how kidney podocytes (glomerular epithelial cells) regenerate foot processes of the filtration apparatus following injury. Recently identified sarcomere-like structures (SLSs) with periodically spaced myosin IIA and synaptopodin appear in injured podocytes in vivo. We hypothesized that SLSs template synaptopodin in the initial stages of recovery in response to microenvironmental stimuli and tested this hypothesis by developing an ex vivo culture system that allows control of the podocyte microenvironment. Results supported our hypothesis. SLSs in podocytes that migrated from isolated kidney glomeruli presented periodic synaptopodin-positive clusters that nucleated peripheral, foot process-like extensions. SLSs were mechanoresponsive to actomyosin inhibitors and substrate stiffness. Results suggest SLSs as mechanobiological mediators of podocyte recovery and as potential targets for therapeutic intervention.

Transcatheter Examination of the Peritoneal Dialysis Catheter with the SpyGlass Direct Visualization System: A New Aid in Diagnosis and Salvation of Ultrafiltration Failure from Partial Catheter Obstruction.

Mechanical complications in peritoneal dialysis (PD), including intraluminal clogging of the PD catheter by fibrin, omentum, or blood clot, are major causes of outflow problems and, in rare cases, lead to technical failure. To visualize an intraluminal image of patients undergoing PD with ineffective ultrafiltration (UF), a SpyGlass fiber optic probe was inserted into the catheter, together with SpyBite biopsy forceps, should the removal of clogging materials be needed. Applying these transcatheter devices in 2 PD patients with unexplained UF failure led to the demonstration of omental plugging at the catheter tip in the first patient and demonstration of intraluminal blood clots in the second patient from whom clots were removal successfully. Both patients achieved better UF volume thereafter without procedure-related complications.